92 3.1 w/78K. Car often sits for a month or more with knife switch on Pos cable in open pos. Took it out the other day, let it warm up for about 15 min, shifted between D, R and N a few times and then drove about 1mi at 30MPH and then about 10min at 65MPH. Coolant Temp light started to glow dimly. Stopped to check for leaks and found none. Started up again and continued. Light would slowly brighten and dim. Then light came on solid but with no ill effects. Drove at 70MPH for several hrs with light on solid and no other symptoms. Shut engine off for over an hour and when I restarted, light was on solid again. I'm thinkin' bad sensor. Am I correct and if so, where is it located and is it easily replaced? I used to do all my own repairs but that was back before computers and when engines still breathed through carbuerators. HAH! Still handy with tools but leery of my "puppy paws." I guess the biggest job I'd done (in the street) was replacing head gaskets on a 73 Olds. so you can get an idea of my abilities.

Scan it and see if the temp sensor reads high, the coolant temp sensor is right near the thermostat housing, 2 wire unit.

Here comes my ignorance. What do you mean by "scan it."

OK, I got it, Thanks.

There is a separate sensor in the rear cylinder head that operates the temp guage/idiot light. It is located toward the drivers side, just above Cyl-5 and has an 8-inch or so long green wire attached. If the fans are coming on, and the car isn't actually overheating (puking coolant, steaming, etc...), then I'd suspect it is your issue.